The Apnea–Hypopnea Index (AHI) is an index used to indicate the severity of sleep apnea. It is represented by the number of apnea events per hour of sleep. The apneas (pauses in breathing) must last for at least 10 seconds and be associated with a decrease in blood oxygenation. A healthy person without sleep apnoea will typically have no more than 5 events an hour.
For mild/moderate/severe sleep apnoea, you may be recommended CPAP therapy as well a range of lifestyle changes such as weight loss and exercise.
If you go on CPAP therapy, one of the likely goals will be to reduce your AHI score to a healthier level.